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New study by Surya Gayet in Journal of Neuroscience

Enhanced neural response to visual input that matches the content of visual working memory

When we are searching for a friend on a festival terrain, we will seek to use a strategy that facilitates detection of everything that visually resembles our friend, at the expense of everything that does not. In order to do this, we (implicitly) generate a crude mental representation of our friend, based on a simple visual attribute. For instance, if our friend is wearing a red t-shirt, this mental representation could consist of only the color red. Active maintenance of the color red in our mind’s eye (or in vision scientists’ terms: in visual working memory) then allows for favoring concurrent visual input that is red over visual input that is not, which then helps us to find our friend. This strategy works not only on a festival terrain, but in the lab as well: visual input that matches the content of visual working memory has been shown to attract attention, and eye-movements, and gains preferential access to consciousness.

In this functional MRI Experiment, we demonstrate for the first time how this is achieved by the visual system: visual input elicits an enhanced neural response when it matches the content of visual working memory. Importantly, this enhancement was not only in terms of signal strength (i.e., ‘more’ brain activity), but also in terms of information content (i.e., a more informative pattern of neural activity). In this publication we suggest that the interaction between visual working memory and visual input is allowed for by a common neural substrate, such that any visual representation (e.g., of the color red) draws upon the same neural circuitry, irrespective of whether it is generated by visual working memory or by visual input.